Article

Sibling composition during childhood and adult blood pressure among native Amazonians in Bolivia

Heller School for Social Policy and Management, Brandeis University, Waltham, MA 02454-9110, USA. Electronic address: .
Economics and human biology (Impact Factor: 1.9). 09/2012; 11(3). DOI: 10.1016/j.ehb.2012.08.002
Source: PubMed

ABSTRACT

Sibling configuration, including birth order, or the number, age, and sex of siblings is associated with parental resource allocation between children and is thus associated with a person's well-being. Little is known about the association between specific types of siblings and adult health outcomes. Here we test several hypotheses about sibling composition (number of older brothers, older sisters, younger sisters, younger brothers) and adult blood pressure in a foraging-farming society of native Amazonians in Bolivia (Tsimane'). We collected data in 2007 from 374 adults (16-60years of age) from 196 households in 13 villages. Household random-effects multiple regressions were run using systolic (SBP) or diastolic blood pressure (DBP) as outcomes; covariates included the four sibling categories and control variables (e.g., sex, age, education, body mass index [BMI]). Mean SBP and DBP were 114 (SD=14) and 66 (SD=11)mmHg. The prevalence of hypertension was 5.08%. Having an additional younger brother bore a small (3.3-5.9%) positive association with both SBP and DBP, with the effect weakening as people aged. Having an additional younger sister was associated with a small (3.8%) increase in SBP among women, with the magnitude shrinking as people aged. In a large family, the number of younger brothers may exert an impact on an individual's blood pressure.

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    • "In populationbased studies, the Tsimane' have one of the lowest reported cortisol concentrations, a stress-related biomarker (Nyberg, 2012). Adult blood pressure is slightly above other native Amazonian societies , with 4e6% having hypertension (Gurven et al., 2012; Zeng et al., 2013b). About 33e40% of Tsimane' children are growth-stunted (Foster et al., 2005; Godoy et al., 2010), and have low hemoglobin levels (Lindsay et al., 2003). "
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    ABSTRACT: Research suggests that poorer people have worse health than the better-off and, more controversially, that income inequality harms health. But causal interpretations suffer from endogeneity. We addressed the gap by using a randomized control trial among a society of forager-farmers in the Bolivian Amazon. Treatments included one-time unconditional income transfers (T1) to all households and (T2) only to the poorest 20% of households, with other villages as controls. We assessed the effects of income inequality, absolute income, and spillovers within villages on self-reported health, objective indicators of health and nutrition, and adults' substance consumption. Most effects came from relative income. Targeted transfers increased the perceived stress of participants in better-off households. Evidence suggests increased work efforts among better-off households when the lot of the poor improved, possibly due to a preference for rank preservation. The study points to new paths by which inequality might affect health.
    Full-text · Article · Jan 2016 · Social Science [?] Medicine